1. Field of the Disclosure
This present disclosure relates to instruments and methods for performing minimally invasive, laparoscopic or endoscopic surgical procedures. More particularly, the present disclosure relates to instruments and methods that are especially suitable for procedures that require or benefit from minimally invasive access to anatomical conduits or vessels for harvesting the same. The instrument is suitable for harvesting vessels from surrounding tissue for use in bypass procedures including, but not limited to, coronary artery bypass grafting (CABG) or reverse or in-situ femoral-popliteal or femoral-tibia peripheral bypass grafting.
2. Related Art
Coronary artery disease is often characterized by lesions or occlusions in the coronary arteries which may result in inadequate blood flow to the myocardium, or myocardial ischemia, which is typically responsible for such complications as angina pectoris, necrosis of cardiac tissue (myocardial infarction), and sudden death. In some cases, coronary artery disease may be treated by the use of drugs and/or by modifications in behavior and diet. In other cases, dilatation of coronary arteries may be achieved by such procedures as angioplasty, laser ablation, atherectomy, catheterization, and intravascular stents. Coronary bypass surgery is required when these methods of treatment cannot be used or have failed to clear the blocked artery.
Many surgical procedures have been developed to replace arteries that have come blocked by disease. For certain patients, a coronary artery bypass graft (“CABG”) is the preferred form of treatment to relieve symptoms and the graft often increases life expectancy. A CABG procedure consists of direct anastomosis of a vessel segment to one or more of the coronary arteries. For example, a reversed segment of the saphenous vein may be grafted at one end to the ascending aorta as an arterial blood source and at the other end to a coronary artery at a point beyond the arterial occlusion.
Therefore and in order to perform a CABG procedure, a vessel must be harvested from the body and grafted into place on either side of the point of blockage. It is preferred to use a vein taken from the patient undergoing the bypass surgery to avoid and/or limit the chances of rejection by the body after grafting onto the aorta and coronary artery. The saphenous vein in the leg is often the most suitable candidate for use in coronary bypass surgery because the saphenous vein is typically 3 mm to 5 mm in diameter which is about the same size as a coronary artery. The cephalic vein in the arm is another suitable harvesting candidate for CABG procedures.
As can be appreciated, harvesting these conduits from the body often requires enormous skill and precision due to the delicate nature of the tissue structure. Various methods for harvesting vessels are known. For example, some surgeons typically cut the leg open and carefully dissect the surrounding tissue from the vein using dissecting scissors or tissue scraping instruments. Other surgeons make a series of incisions from the groin to the knee or the ankle leaving one or more skin bridges along the line of the incisions. The surgeon then literally strips the vein free from surrounding tissue using one or more surgical dissecting instruments.
While stripping the vein and removing the surround tissue, the surgeon will undoubtedly encounter the various tributary veins that feed into the saphenous vein. These tributaries must be ligated and separated from the vein prior to removal. As can be appreciated, ligating and separating these tributaries from the vein requires a high degree of skill and accuracy and is typically a very tedious procedure.
When the vein has been completely mobilized and the tributaries have been divided from the vein, the surgeon cuts the proximal and distal ends of the vein and removes the vein from the leg. Once removed, the vein is prepared for implantation into the graft site, and the long incision(s) made in the leg are stitched closed.
The procedures described above are often used to harvest veins for a femoral popliteal bypass or for the revascularization of the superior mesenteric artery which supplies blood to the abdominal cavity and intestines. In addition, the above-described procedures can be used to harvest the umbilical vein or to harvest veins for femoral-tibial, femora-peroneal, aorto-femoral, and iliac-femoral bypass operations and any other bypass operation.
As can be appreciated from the above descriptions, the harvesting of vessels can be very traumatic and is often the most troublesome part of the bypass operation. Moreover, the incisions, especially the long ones, created in the leg or arm to harvest the vessel tend to heal slowly and are often very painful.
Over the last several years, minimally invasive, for example endoscopic tools and methods have been developed for harvesting vessels which are less intrusive and less traumatic. For example, with one known technique, the surgeon makes a few small incisions in the leg and inserts one or more elongated surgical instruments, e.g., forceps, scissors, clip appliers, staplers, etc., into the incision and carefully manipulates the instruments while viewing the operating area through an endoscopic or laparoscope. These techniques are often referred to as endoscopic, laparoscopic, minimally invasive, or video-assisted surgery. References to endoscopic surgery and endoscopes below is intended to encompass all these fields, and the exemplary operations described below with reference to endoscopes can also be accomplished with laparoscopes, gastroscopes, and any other imaging devices which may be conveniently used.
Other minimally invasive procedures for vein harvesting are also known. For example, soviet patent number SU 1371689 teaches a vessel removal procedure which utilizes an endoscope having a lumen extending therethrough. In this procedure, the saphenous vein is grasped and held with a grasper which is introduced through the lumen of the endoscope. After connective tissue has been dissected from around the vein, a length of the vein is ligated, transected and removed from the lower limb of the patient through the lumen of the endoscope. U.S. Pat. No. 5,373,840 discloses a method for harvesting the saphenous vein which also utilizes an endoscope having a lumen disposed therethrough.
Other known techniques employ balloons which are inflated to create a working cavity or tunnel along the length of the vein. For example, U.S. Pat. No. 5,601,581 describes a method of vein harvesting which utilizes an everted balloon to assist in dissecting the harvested vein. The balloon is stored inside a cannula which is inserted through one of the small incisions in the leg and inflated so that it everts out the end of the cannula and forces its way along the vein to create a tunnel.
Typically, many of the above-described techniques require the surgeon to insert different instruments through the working lumen of the endoscope to dissect tissue and to separate vessel tributaries. As can be appreciated, this simply adds to the overall complexity of the operation since it requires the repeated exchange of surgical instruments through the working lumen to perform the different tasks associated with blunt dissection and removal of the vessel tributaries.
Thus, a need exists to develop an endoscopic vessel harvesting instrument and method for harvesting vessels which allows the operator to both dissect surrounding tissue from the vein and selectively manipulate, grasp and separate vessel tributaries from the vein without removing and/or exchanging instruments through the working lumen.